A SIMPLE-MODEL FOR TRANSFORMER INRUSH CURRENT CALCULATION AND HARMONIC-ANALYSIS

Measurements of transformer inrush current offer important data for power system operation and protection. Since inrush current is the result of a system transient, it is difficult to observe this phenomenon and analyze its effect instantaneously. This paper proposes a simple model to represent and simulate the magnetizing inrush current of transformers using real-time measurements. The proposed method formulates a simplified model to represent the inrush current under different loading conditions. The simulation data are also used for harmonic analysis. The relationship of the harmonics to all parameters is discussed. The proposed simulation results are compared with the experimental results with very good agreement. The results establish a guideline for elimination of harmonics due to inrush current, and offer an important reference for system design considerations.